Boxy/peanut/X bulges, barlenses and the thick part of galactic bars: What are they and how did they form?

Bars have a complex three-dimensional shape. In particular their inner part is vertically much thicker than the parts further out. Viewed edge-on, the thick part of the bar is what is commonly known as a boxy-, peanut- or X- bulge and viewed face-on it is referred to as a barlens. These components are due to disc and bar instabilities and are composed of disc material. I review here their formation, evolution and dynamics, using simulations, orbital structure theory and comparisons to observations.Comment: 21 pages, 7 figures, invited review to appear in "Galactic Bulges", E. Laurikainen, R. Peletier, D. Gadotti, (eds.), Springe

PolyView : an object-oriented data model for supporting multiple user views

In a typical database application, there are many different users with a great variety of skills, needs and perceptions. The problem of supporting this plethora of user views in a dynamic, data intensive environment is the topic of this dissertation.In traditional record-based systems, all information is represented by an idealized data structure and a set of operations on that structure. User views are defined by simple variations in this structure, such as permuting field names, selecting a subset of the data, or creating links between records. Semantic database models support more complex, "natural" structures. It is often claimed that relativism is supported because semantic schemas can be correctly interpreted (by users) in different ways. The object-oriented paradigm, with its simple and elegant structural semantics, provides both simplicity and richness. Unfortunately, current object-oriented systems only provide a single object interface (or protocol). This dissertation presents PolyView; an object-oriented data model capable of simultaneously supporting many points of view. In PolyView, objects encapsulate a single structure and any number of object interfaces (view instance descriptions). PolyView, therefore, supports distributed mappings from user views to the underlying database structure.Algorithms are presented for generic methods which retrieve and update information through user views. PolyView "colors" queries (messages) by attaching a view identity to them. As messages are propagated through the schema, each receiving object uses the color to determine how the message is to be processed. The color is used to select the user's protocol and allows different user's queries to be processed through apparently different database structures. Because objects act independently, PolyView is a data-driven system; messages are processed without any centralized control or shared memory.Finally, PolyView provides a set of view transformations which allow view administrators to build object interfaces. Since views are supported by both global and localized mechanisms, there are transformations which operate at each of these levels. There are three major categories of transformations presented in this thesis: those which customize the schema as a whole, transformations for changing the structure of the IS-A hierarchy and transformations for customizing attributes

Research Project as Boundary Object: negotiating the conceptual design of a tool for International Development

This paper reflects on the relationship between who one designs for and what one designs in the unstructured space of designing for political change; in particular, for supporting “International Development” with ICT. We look at an interdisciplinary research project with goals and funding, but no clearly defined beneficiary group at start, and how amorphousness contributed to impact. The reported project researched a bridging tool to connect producers with consumers across global contexts and show players in the supply chain and their circumstances. We explore how both the nature of the research and the tool’s function became contested as work progressed. To tell this tale, we invoke the idea of boundary objects and the value of tacking back and forth between elastic meanings of the project’s artefacts and processes. We examine the project’s role in India, Chile and other arenas to draw out ways that it functioned as a catalyst and how absence of committed design choices acted as an unexpected strength in reaching its goals

Working Notes from the 1992 AAAI Workshop on Automating Software Design. Theme: Domain Specific Software Design

The goal of this workshop is to identify different architectural approaches to building domain-specific software design systems and to explore issues unique to domain-specific (vs. general-purpose) software design. Some general issues that cut across the particular software design domain include: (1) knowledge representation, acquisition, and maintenance; (2) specialized software design techniques; and (3) user interaction and user interface

A data augmentation methodology for training machine/deep learning gait recognition algorithms

There are several confounding factors that can reduce the accuracy of gait recognition systems. These factors can reduce the distinctiveness, or alter the features used to characterise gait; they include variations in clothing, lighting, pose and environment, such as the walking surface. Full invariance to all confounding factors is challenging in the absence of high-quality labelled training data. We introduce a simulation-based methodology and a subject-specific dataset which can be used for generating synthetic video frames and sequences for data augmentation. With this methodology, we generated a multi-modal dataset. In addition, we supply simulation files that provide the ability to simultaneously sample from several confounding variables. The basis of the data is real motion capture data of subjects walking and running on a treadmill at different speeds. Results from gait recognition experiments suggest that information about the identity of subjects is retained within synthetically generated examples. The dataset and methodology allow studies into fully-invariant identity recognition spanning a far greater number of observation conditions than would otherwise be possible